<template>
  <div
    class="bin-rate"
    @keydown="handleKey"
    role="slider"
    :aria-valuenow="currentValue"
    :aria-valuetext="text"
    aria-valuemin="0"
    :aria-valuemax="max"
    tabindex="0">
    <span
      v-for="(item, key) in max"
      class="bin-rate__item"
      @mousemove="setCurrentValue(item, $event)"
      @mouseleave="resetCurrentValue"
      @click="selectValue(item)"
      :style="{ cursor: rateDisabled ? 'auto' : 'pointer' }"
      :key="key">
      <i
        :class="[classes[item - 1], { 'hover': hoverIndex === item }]"
        class="bin-rate__icon iconfont"
        :style="getIconStyle(item)">
        <i
          v-if="showDecimalIcon(item)"
          :class="decimalIconClass"
          :style="decimalStyle"
          class="bin-rate__decimal iconfont">
        </i>
      </i>
    </span>
    <span v-if="showText || showScore" class="bin-rate__text" :style="{ color: textColor }">{{ text }}</span>
  </div>
</template>

<script>
  import { hasClass } from '../../utils/dom'

  export default {
    name: 'BRate',
    data () {
      return {
        pointerAtLeftHalf: true,
        currentValue: this.value,
        hoverIndex: -1
      }
    },

    props: {
      value: {
        type: Number,
        default: 0
      },
      lowThreshold: {
        type: Number,
        default: 2
      },
      highThreshold: {
        type: Number,
        default: 4
      },
      max: {
        type: Number,
        default: 5
      },
      colors: {
        type: Array,
        default () {
          return ['#F7BA2A', '#F7BA2A', '#F7BA2A']
        }
      },
      voidColor: {
        type: String,
        default: '#C6D1DE'
      },
      disabledVoidColor: {
        type: String,
        default: '#EFF2F7'
      },
      iconClasses: {
        type: Array,
        default () {
          return ['icon-favorfill', 'icon-favorfill', 'icon-favorfill']
        }
      },
      voidIconClass: {
        type: String,
        default: 'icon-favor'
      },
      disabledVoidIconClass: {
        type: String,
        default: 'icon-favorfill'
      },
      disabled: {
        type: Boolean,
        default: false
      },
      allowHalf: {
        type: Boolean,
        default: false
      },
      showText: {
        type: Boolean,
        default: false
      },
      showScore: {
        type: Boolean,
        default: false
      },
      textColor: {
        type: String,
        default: 'rgba(0,0,0,.65)'
      },
      texts: {
        type: Array,
        default () {
          return ['极差', '失望', '一般', '满意', '惊喜']
        }
      },
      scoreTemplate: {
        type: String,
        default: '{value}'
      }
    },
    computed: {
      text () {
        let result = ''
        if (this.showScore) {
          result = this.scoreTemplate.replace(/\{\s*value\s*\}/, this.rateDisabled
            ? this.value
            : this.currentValue)
        } else if (this.showText) {
          result = this.texts[Math.ceil(this.currentValue) - 1]
        }
        return result
      },
      decimalStyle () {
        let width = ''
        if (this.rateDisabled) {
          width = `${this.valueDecimal < 50 ? 0 : 50}%`
        }
        if (this.allowHalf) {
          width = '50%'
        }
        return {
          color: this.activeColor,
          width
        }
      },
      valueDecimal () {
        return this.value * 100 - Math.floor(this.value) * 100
      },
      decimalIconClass () {
        return this.getValueFromMap(this.value, this.classMap)
      },
      voidClass () {
        return this.rateDisabled ? this.classMap.disabledVoidClass : this.classMap.voidClass
      },
      activeClass () {
        return this.getValueFromMap(this.currentValue, this.classMap)
      },
      colorMap () {
        return {
          lowColor: this.colors[0],
          mediumColor: this.colors[1],
          highColor: this.colors[2],
          voidColor: this.voidColor,
          disabledVoidColor: this.disabledVoidColor
        }
      },
      activeColor () {
        return this.getValueFromMap(this.currentValue, this.colorMap)
      },
      classes () {
        let result = []
        let i = 0
        let threshold = this.currentValue
        if (this.allowHalf && this.currentValue !== Math.floor(this.currentValue)) {
          threshold--
        }
        for (; i < threshold; i++) {
          result.push(this.activeClass)
        }
        for (; i < this.max; i++) {
          result.push(this.voidClass)
        }
        return result
      },
      classMap () {
        return {
          lowClass: this.iconClasses[0],
          mediumClass: this.iconClasses[1],
          highClass: this.iconClasses[2],
          voidClass: this.voidIconClass,
          disabledVoidClass: this.disabledVoidIconClass
        }
      },
      rateDisabled () {
        return this.disabled
      }
    },
    watch: {
      value (val) {
        this.currentValue = val
        this.pointerAtLeftHalf = this.value !== Math.floor(this.value)
      }
    },
    methods: {
      getMigratingConfig () {
        return {
          props: {
            'text-template': 'text-template is renamed to score-template.'
          }
        }
      },
      getValueFromMap (value, map) {
        let result = ''
        if (value <= this.lowThreshold) {
          result = map.lowColor || map.lowClass
        } else if (value >= this.highThreshold) {
          result = map.highColor || map.highClass
        } else {
          result = map.mediumColor || map.mediumClass
        }
        return result
      },
      showDecimalIcon (item) {
        let showWhenDisabled = this.rateDisabled && this.valueDecimal > 0 && item - 1 < this.value && item > this.value
        /* istanbul ignore next */
        let showWhenAllowHalf = this.allowHalf &&
          this.pointerAtLeftHalf &&
          item - 0.5 <= this.currentValue &&
          item > this.currentValue
        return showWhenDisabled || showWhenAllowHalf
      },
      getIconStyle (item) {
        const voidColor = this.rateDisabled ? this.colorMap.disabledVoidColor : this.colorMap.voidColor
        return {
          color: item <= this.currentValue ? this.activeColor : voidColor
        }
      },
      selectValue (value) {
        if (this.rateDisabled) {
          return
        }
        if (this.allowHalf && this.pointerAtLeftHalf) {
          this.$emit('input', this.currentValue)
          this.$emit('change', this.currentValue)
        } else {
          this.$emit('input', value)
          this.$emit('change', value)
        }
      },
      handleKey (e) {
        if (this.rateDisabled) {
          return
        }
        let currentValue = this.currentValue
        const keyCode = e.keyCode
        if (keyCode === 38 || keyCode === 39) { // left / down
          if (this.allowHalf) {
            currentValue += 0.5
          } else {
            currentValue += 1
          }
          e.stopPropagation()
          e.preventDefault()
        } else if (keyCode === 37 || keyCode === 40) {
          if (this.allowHalf) {
            currentValue -= 0.5
          } else {
            currentValue -= 1
          }
          e.stopPropagation()
          e.preventDefault()
        }
        currentValue = currentValue < 0 ? 0 : currentValue
        currentValue = currentValue > this.max ? this.max : currentValue
        this.$emit('input', currentValue)
        this.$emit('change', currentValue)
      },
      setCurrentValue (value, event) {
        if (this.rateDisabled) {
          return
        }
        /* istanbul ignore if */
        if (this.allowHalf) {
          let target = event.target
          if (hasClass(target, 'bin-rate__item')) {
            target = target.querySelector('.bin-rate__icon')
          }
          if (hasClass(target, 'bin-rate__decimal')) {
            target = target.parentNode
          }
          this.pointerAtLeftHalf = event.offsetX * 2 <= target.clientWidth
          this.currentValue = this.pointerAtLeftHalf ? value - 0.5 : value
        } else {
          this.currentValue = value
        }
        this.hoverIndex = value
      },
      resetCurrentValue () {
        if (this.rateDisabled) {
          return
        }
        if (this.allowHalf) {
          this.pointerAtLeftHalf = this.value !== Math.floor(this.value)
        }
        this.currentValue = this.value
        this.hoverIndex = -1
      }
    },
    created () {
      if (!this.value) {
        this.$emit('input', 0)
      }
    }
  }
</script>
